Equipment frame mounting travelling wave tube and related apparatus



G W. S. GRIFFITH ETAL EQUIPMENT FRAME MOUNTING TRAVELLIN June 15, 1965 V 3,189,792

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EQUIPMENT FRAME MOUNTING TRAVELLING WAVE TUBE AND RELATED APPARATUS Filed March 1, 1962 I 2 Sh eets-Sheet 2 48% l igi/is 12 4s Fig.3

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United States Patent 3,189,792 EQUIPMENT FRAME MOUNTING TRAVELLING WAVE TUBE AND RELATED APPARATUS George William Sapsworth Grifith, Leamington Spa, and Bernard Wilson, Coventry, England, assignors to The General Electric Company Limited, London, England, a British company Filed Mar. 1, 1962, Ser. No. 176,602 Claims priority, application Great Britain, Mar. 3, 1961, 7,851/ 61 3 Claims. (Cl. 317-99) This invention relates to apparatus of the kind which is arranged to mount travelling wave tubes.

A travelling wave tube usually has an elongated evacuated envelope and during use of the tube this envelope is embraced along the major part of its length by a focussing device which comprises one or more magnets for the purpose of obtaining the desired electron beam within the tube. In order to remove the travelling wave tube for the purpose of replacement, it is usual to draw it out longitudinally from its associated focussing device and accordingly the focussing device must be mounted in a position which. gives sufficient clear space for the travelling wave tube to be drawn out of the focussing device. This is particularly a problem in the case of a travelling wave tube mounted on a rack of other framework and one object of the present invention is to provide a construction of apparatus in which this difficulty is largely overcome.

According to the present invention, apparatus which is arranged to mount a travelling wave tube has the focussing device for the travelling wave tube carried on a structure which is moveable relative to a framework which supports the structure, the arrangement being such that the focus sing device lies at least mainly within the framework during normal operation of the apparatus so that a travelling wave tube cannot then be inserted in or removed from the focussing device although the device is capable of being moved to a position such that a travelling wave tube may readily be so inserted or removed.

The structure, which may be pivoted to the framework, may carry other components or items of equipment, for example an oscillation generator, a frequency changer, etc., at least some of which are connected in circuit with the travelling wave tube during normal use of the apparatus. If part of the apparatus carried by the structure is arranged to supply an oscillatory signal, a flexible transmission line, for example a waveguide, may be provided to carry that signal, this transmission line being arranged to bend when the structure is moved as aforesaid.

A rack of equipment which is for the transmitting terminal of a point-to-point radio link and which is in accordance with the present invention will now be described by way of example with reference to the six figures of the accompanying drawings in which:

FIGURE 1 shows diagrammatically the circuit of the equipment mounted on the rack,

FIGURE 2 shows a front elevation of the rack with the front covers removed,

FlGURE 3 shows a side elevation of the rack with the front covers and side panels removed,

FlGURE 4 shows an enlarged view at the line IVIV in FIGURE 2,

FIGURE 5 shows an enlarged view at the line V-V in FIGURE 2 and FIGURE 6 shows an enlarged cross-section at the line VIVI in FIGURE 2.

Referring first to FIGURE 1, the equipment comprises a frequency multiplier 1 to which the oscillations supplied by an oscillator 2 are passed via an amplifier 3. A band pass filter 4 is arranged to select from the signal supplied by the frequency multiplier 1, oscillations having a fie- 3,189,792 Patented June 15, 1965 quency that is a particular harmonic of the frequency of the oscillator 2 and in one arrangement the selected oscillations have a frequency of several thousand megacycles per second. The oscillations passed by the filter 4 are fed to a frequency changer 5 Where they are heterodyned with signals supplied by an amplifier-limiter 6. The amplifier-limiter 6 is arranged to pass the signal supplied thereto over a path 7 and this signal may, for example, consist of oscillations having a mean frequency of megacycles per second that are frequency modulated by several hundred speech signals combined in frequency division multiplex.

A band pass filter 8 is arranged to select one side band of the signal supplied by the frequency changerS and this side band signal is passed through a travelling wave tube amplifier 9 and a band pass filter 10 to an output path 11.

Referring now also to FIGURES 2 and 3 of the accompanying drawings, the equipment shown in FIGURE 1 is all mounted on a vertical rack 12 that stands on the floor. The oscillator 2 and the amplifier limiter 6 together with power supplies (not shown) for the equipment are mounted on the main framework 14 of the rack 12 towards the bottom thereof. The remaining items of the equipment, namely those contained Within the broken line 13 in FIGURE 1, are mounted on a structure 15 that is pivoted to the rack framework 14. In particular the travelling wave tube amplifier 9 is mounted at the bottom of the structure 15.

The structure 15 is generally in the shape of a rightangled wedge and is formed by members 16 to 20 each of which lies generally along one edge of the wedge a rectangular plate 21 which constitutes a deck on which the various items of equipment are mounted, and cross members 22 and 23. The structure 15 is pivoted by means of two pins 24 and 25 which project from the sides of the wedge" and which lie respectively in recesses in two mounting blocks 26 and 27 carried by the framework 14. FIGURE 4 shows more clearly the manner in which the pin 24 engages the supporting block 26.

During normal operation of the equipment the structure 15 is in the position shown in FIGURE 3 with the plate 21 vertical. It is held in this position by means of two spring-loaded catches 28 and 29 which fit into holes in members 39 and 31 respectively, these members 30 and 31 being secured to the rack framework 14. The catch 29, for example, engages a hole 40 in the member 31 as shown in FIGURE 5. When the catches 2S and 29 are pulled by hand clear of the holes in the members 30 and 31, the structure 15 may be pivoted out to the position shown by the chain outline 15 and the structure may be held in this position by the catch 29, say, springing into the hole 32 (FIGURE 5 in the member 31.

The manner in which the items 1, 3, 4, 5, 3, 9 and 1t) are disposed on the structure 15 is shown in FIGURE 2, items 1, 3, 4, 5, 8 and 10 all being secured, for example by bolts, directly to the deck 21. It will be seen that the amplifier 3 is connected to the frequency multiplier 1 by way of a length 33 of co-axial cable. All other connections are over waveguides of rectangular cross-section, the frequency multiplier 1, for example, having an output waveguide section 34 which is connected to the input end of the filter 4.

The output waveguide section 35 of the filter 8 is connected over a length 36 of waveguide and a waveguide transition section 37 to the input waveguide 33 of the travelling wave tube amplifier 9. The output waveguide 39 of the travelling wave tube amplifier 9 is connected to the input waveguide section 41 of the filter 10 while a length 42 of waveguide is connected to the output waveguide section 43 of the filter. The flange 44 at the end of the length 42 of waveguide remote from the filter 10 is fixed to the deck 21 by means of a bracket 45.

The flange 44 is bolted to the flange 4-6 of a length 27 of flexible waveguide and this waveguide is connected at the other end to a length 58 of rigid waveguide which constitutes an aerial feeder. This length 48 of waveguide is fixed relative to the rack framework 14' and, for this purpose, may conveniently be secured to a fixed member (not shown) that is located above the rack 12. It will be appreciated that this arrangement enables the structure 15 to be pivoted out to the position 15 without having to disconnect any waveguide connections.

It is now convenient to consider in more detail the travelling wave tube amplifier 9 which may be a type TWCS manufactured by The M-O Valve Co. Ltd. Referring also to FIGURE 6, the amplifier 9 comprises a travelling wave tube having an elon ated glass envelope 51 and an associated focussing device 52 which normally embraces the tube 5il. The focussing device 52 is of the periodic magnetic focussing type and comprises a series of annular permanent magnets 53 which alternate with soft iron pole pieces 5 each pair of adjacent magnets 53 having like poles disposed adjacent each other.

At the cathode end of the tube 59, electric wires 55 are soldered at one end to terminal pins 56 of the tube. The other ends of these wires 55 are connected to a multi-way plug 57 which engages a multi-way socket 53, a group of wires (shown collectively with the reference 59) being in turn connected to the socket 58.

The openings 61 and 62 of the input waveguide 38 and the output waveguide 3% of the travelling wave tube amplitier 9 may be seen in FIGURE 6.

A metal cylinder 63 is secured to the end of the glass envelope to provide the collector electrode of the tube 50. This cylinder 63 is also gripped by a device 64 which acts in the manner of a collet chuck to prevent the tube 50 being withdrawn from the focussing device 52 during normal use. i

The focussing device 52 containing the travelling wave tube Ed is mainly supported by hanging from the input waveguide 33 and the output waveguide 39. For example the flange 64 of the input waveguide 38 is bolted to the flange 65' of the transition section 37 so as to support one end of the focussing device 52. In addition the focussing device 52 is positioned by being embraced by two clamps 66 and 67 (FIGURE 2) and the clamp 67, for example, is connected to the deck 21 by means of a pair or" pillars 63 (FIGURE 3).

Electrical connections to the items mounted on the structure are by way of sockets mounted on the rack framework 14 and plugs mounted on the structure 15. For example the oscillator 2 is connected by way of a lead 74 to a socket 75 carried by the rack framework 14, this socket engaging a plug 76 which is carried by the structure 15 and which is connected to the amplifier 3 over a lead 77. These plugs and sockets (which are not all shown in the drawings) engage one another when the structure 15 is in the position shown in FIGURE 3 but when it is pivoted out to the position I5 as aforesaid, each of these plugs is withdrawn from its associated socket. Interlocks may be provided to ensure that a plug carrying high voltage electric supplies, say to the collector electrode of the travelling wave tube St? is withdrawn from its associated socket before the structure 15 is moved from its normal position.

It will be appreciated that it would not be possible to remove the travelling wave tube 5% from its associated focussing device 52 while the structure 15 is in the position shown in FIGURE 3 due to the presence of the side panel 69. The procedure for removing or replacing the tube 54 is first to swing the structure 15 to the position 15' FIGURE 3) in the manner previously described. The end cap 71 of the travelling Wave tube amplifier 9 is then removed to expose the plug 57 and socket 58. This plug 57 is removed from the socket 58 and the grip on the cylinder 63 by the device 64 is relaxed by turning a screw 72. The travelling wave tube 50 may then be withdrawn from the focussing device 52 in the direction of the arr-ow 73. To insert a travelling wave tube into the focussing device 52, the procedure just described is reversed.

Although not shown in the drawings, a front cover is normally fixed to the rack framework 14, this cover extending over at least the structure 15. It is of course necessary to remove this cover before the structure 15 is moved to the position 15 (FIGURE 3).

We claim:

1. Apparatus comprising a framework with a back and sides defining a container with an open front, a structure, means supporting said structure only for pivotal movement in said framework about an axis parallel to the open front of the container between a first normal operative position and a second removing or replacing position, an elongated travelling wave tube and an associated focussing device, said tube being mounted to lie mainly within the focussing device and to be removable from said focussing device in a direction parallel to the longitudinal axis of the tube, means mounting said focussing device on said structure with the longitudinal axis of the tube parallel to the open front of the container and having a substantial component parallel to the axis of rotation of the pivotal mounting means, and means to provide electrical connection to the travelling wave tube, the travelling wave tube and the focussing device lying at least mainly within the framework when said structure is in said first position so that the travelling wave tube cannot then be withdrawn from the focussing device and said travelling wave tube being clear of said framework in said second position so that the travelling wave tube may readily be withdrawn from or replaced in the focussing device.

2. An apparatus as set forth in claim 1 wherein the longitudinal axis of the travelling wave tube is parallel to the axis of rotation of the pivotal mounting means.

3. An apparatus as set forth in claim 1 wherein an electrical component is carried by said framework and wherein the means to provide electrical connection to the travelling wave tube includes a flexible wave guide that passes close to the axis of rotation of the pivotal mounting means and is included in the electrical connection from the travelling wave tube to said component.

References (Iited by the Examiner UNITED STATES PATENTS 2,769,940 11/56 Pettit 317l20 2,904,725 9/;59 Lebedinsky 3l799 3,012,172 12/61 Kammer et al 3l7--101 OTHER REFERENCES Electronics, New Products, edited by W. P. OBrien, March 1955 (page 324).

JOHN F. BURNS, Primary Examiner.

GEORGE N. WESTBY, Examiner. 

1. APPARATUS COMPRISING A FRAMEWORK WITH A BACK AND SIDES DEFINING A CONTAINER WITH AN OPEN FRONT, A STRUCTURE, MEANS SUPPORTING SAID STRUCTURE ONLY FOR PIVOTAL MOVEMENT IN SAID FRAMEWORK ABOUT AN AXIS PARALLEL TO THE OPEN FRONT OF THE CONTAINER BETWEEN A FIRST NORMAL OPERATIVE POSITION AND A SECOND REMOVING OR REPLACING POSITION, AN ELONGATED TRAVELLING WAVE TUBE AND AN ASSOCIATED FOCUSING DEVICE, SAID TUBE BEING MOUNTED TO LIE MAINLY WITHIN THE FOCUSSING DEVICE AND TO BE REMOVABLE FROM SAID FOCUSSING DEVICE IN A DIRECTION PARALLEL TO THE LONGITUDINAL AXIS OF THE TUBE, MEANS MOUNTING SAID FOCUSSING DEVICE ON SAID STRUCTURE WITH THE LONGITUDINAL AXIS OF THE TUBE PARALLEL TO THE OPEN FRONT OF THE CONTAINER AND HAVING A SUBSTANTIAL COMPONENT PARALLEL TO THE AXIS OF ROTATION OF THE PIVOTAL MOUNTING MEANS, AND MEANS TO PROVIDE ELECTRICAL CONNECTION TO THE TRAVELLING WAVE TUBE, THE TRAVELLING WAVE TUBE AND THE FOCUSSING DEVICE LYING AT LEAST MAINLY WITHIN THE FRAMEWORK WHEN SAID STRUCTURE IS IN SAID FIRST POSITION SO THAT THE TRAVELLING WAVE TUBE CANNOT THEN BE WITHDRAWN FROM THE FOCUSSING DEVICE AND SAID TRAVELLING WAVE TUBE BEING CLEAR OF SAID FRAMEWORK IN SAID SECOND POSITION SO THAT THE TRAVELLING WAVE TUBE MAY READILY BE WITHDRAWN FROM OR REPLACED IN THE FOCUSSLING DEVICE. 